Water-soluble polymers (WSPs) are well known in the prior art as rheology modifiers of aqueous functional systems. For instance, they are used as thickeners for a wide range of functional systems such as for latex paints, oil-well servicing fluids, cosmetics, personal care products, construction and building products, Civil Engineering applications, household care products, food, and paper manufacturing products. Civil Engineering applications include diaphragm walling and trenching, pilling, water-well drilling, horizontal drilling and tunneling. It is also well known that these WSPs sometimes have problems of lumping, dispersability, and pourability in dry form. Therefore, dispersions or fluid polymer systems (FPS) are well accepted in many industries.
The most commonly used WSPs as thickeners are guar and guar derivatives, carboxymethylcellulose (CMC), and hydroxyethylcellulose (HEC). All these products have been patented in dispersions or suspensions (or FPS) systems for various uses using organic carriers such as fatty acids, diesel or mineral oils. Current technologies for CMC, HEC and guar/derivatives suspensions are based on the use of either fatty acids and/or mineral oil as the carrier. Both of these technologies have limitations in certain markets.
Polyethylene glycol (PEG) is used widely in many industries, especially the low molecular weight products. Ethylene glycol and its lower polyglycols are colorless, odorless, hygroscopic liquids that have high boiling point and are completely miscible in water and many organic liquids. PEG markedly reduces the freezing point of water. PEG at low level can be administered orally and has been approved by the Food and Drug Administration.
PEG has a variety of uses. In the food industry, it is used as a solvent, humectant, and preservative, in the manufacture of products that come in contact with food such as plasticizers for food wraps, as a solvent for food processing, and as lubricant for food machinery. It is a softening agent, spreader, emollient, intermediate, drug vehicle and preservative in the preparation of cosmetics and pharmaceuticals. Aqueous solutions of PEG are effective antifreeze mixtures and are preferred in refrigeration units in breweries, dairies and packing houses, where a coolant or heat-transfer solution of low toxicity is important. These aqueous solutions prevent rust and corrosion.
U.S. Pat. No. 5,932,193, (J-P Lopez, M. Melbouci, and G. Dewald) discloses an invention involving the use of a PEG based suspension for use in toothpaste formulations. All additives in the slurry composition are used in oral care applications. The preferred composition of the suspension was specified as (a) 40-60% of polyethylene glycol, (b) 0.5-2.0% of amorphous fumed silica, and (c) 40-60% of CMC.
U.S. Pat. No. 5,487,777 (Lunden et al) discloses stable carboxymethyl cellulose (CMC) slurries of 10-60 wt % of CMC, 40-60 wt % of water-soluble polyethylene glycol, and 1-50 wt % of an inert powder or dispersion. This slurry is used as a rheology modifier in aqueous liquid applications such as clarification of water, treatment of minerals, the thickening of foodstuffs and medication, the thickening of farm products, the use of oil drilling liquids, the use of building materials, and the modification of latex colors.
U.S. Pat. No. 4,799,962 (Ahmed) discloses dispersions of water-soluble polymers in low molecular weight polyethylene glycol, water, and high molecular weight polyethylene glycol in amounts sufficient to impart stability to the dispersion. These dispersions are used in latex paints.
U.S. Pat. No. 6,093,769 (Burdick et al.) discloses fluidized polymer suspensions of cationic polysaccharides, stabilizing agent and water-soluble polyols. The preferred cationic polysaccharides are cationic guar and cationic hydroxypropyl guar. Process for preparing personal care compositions utilizing fluidized polymer suspensions in the process provides advantages of more rapid dissolution and avoidance of lumps and gels when compared to powdered cationic polysaccharides.
Since it is well known in the prior art that the use of dry polysaccharides and prior art dispersion techniques are time consuming, inefficient, and not at all time compatible with the functional systems in which they are added, there remains a need in the industry for incorporating water-soluble binder polymers in to functional systems which provide lump-free products, rapid viscosity development, reduced batch preparation time, compatibility, and convenient handling of the binder.
None of the above mentioned prior art meets all of the requirements of the needs of the industries.